Research On GMAW-P Welding Signal Acquisition And Quality Testing Based On WLAN

Gas Melt Arc Welding-Pulse(GMAW-P) is a very efficient welding process. GMAW-P is suitable for all position welding, heat input stability, nice weld appearance, etc.Now it is widely applied in more and more fields. GMAW-P welding process associated with a large amount of signal, among these signals, the largest study and most easily monitoring is electrical signals and weld pool images. Electrical signals includes arc voltage and welding current, which determine the arc stability, drip transitional forms, weld defects and other characteristics.Weld pool images reflect appearance and defects of weld clearly and intuitively.This paper regards electrical signals and weld pool images as the analyzing signals,design a parameters acquisition and quality testing system based on Lab VIEW.The system consists of hardware and software,the parameters transmission module of hardware using WLAN instead of traditional cable transmission. WLAN is the fastest-growing area in recent years, It has low cost, high flexibility, easy installation and other traditional wired network incomparable advantages, more and more WLAN applications in welding field has been put forward.The signal acquisition module consists of hall element, signal conditioning circuit, data acquisition card and CCD camera. Welding current,arc voltage and weld pool images can be collected by signal acquisition module.The collected signals can be analysised by software part, electrical signal analysis includes filtering, differential analysis,U-I analysis, power analysis, correlation analysis, frequency spectrum analysis, probability and statistics analysis module. Weld pool images analysis includes image enhancement, histogram equalization, binary segmentation, smoothing, edge extraction and geometric parameter calculation module, etc. Through the results of each analysis module, can evaluate the stability of welding process and welding quality.A lot of welding experiments by different process specification proved that the system runs stably, comprehensive functions. The quality analysis results were consistent with the actual results.These experiments have demonstrated that this system can be used to judge the defects, evaluate weld quality in actual production, and offer the theorial guidance for the welding production.